indefatigable
Definitions
Persisting tirelessly; incapable of being fatigued.
Showing sustained, enthusiastic effort in a task or purpose.
Examples
Despite the grueling schedule, the indefatigable researcher continued her experiments late into the night.
The indefatigable spirit of the volunteers helped rebuild the community center in record time.
He was an indefatigable campaigner for social justice, never once wavering in his commitment to the cause.
Synonyms
tireless unflagging untiring persistent determined diligent assiduous